Three varieties of pulses P, Q and R are mixed in the ratio \(2 : 3 : 5\). The prices of P and Q are Rs. 60 per kg and Rs. 70 per kg respectively. If the mixture is worth Rs. 78 per kg, then the price of R per kg is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Rs. 90
Take 2 kg of P, 3 kg of Q and 5 kg of R, so the mixture weighs 10 kg. Let R cost Rs. \(x\) per kg. The total cost of the three parts equals the cost of the mixture.
\(2 \times 60 + 3 \times 70 + 5x = 10 \times 78\)
\(120 + 210 + 5x = 780\)
\(5x = 450\)
\(x = 90\)
So R costs Rs. 90 per kg.